Waves Sound and Light — Free IB MYP5 Physics Questions

1QuestionVisible Light and Color DispersionConcept Practice

2 marks~3 minCriterion A

The diagram shows white light entering a triangular glass prism and emerging as a spread of colours.

a

State what is meant by dispersion of light. [1]

b

Explain why violet light bends more than red light when passing through the prism, referring to wavelength, frequency, and refraction in your answer. [1]

Solutions

2QuestionComparing EM Waves Speed Wavelength FrequencyConcept Practice

4 marks~6 minCriterion A

A spectrometer in a solar observatory detects a light wave with a period of

T = 2.0 \times 10^{-15}

s. The speed of light is

c = 3.0 \times 10^{8}

m s

^{-1}

.

a

State the equation relating period

T

and frequency

f

. [1]

b

Show that the wavelength of this wave is

6.0 \times 10^{-7}

m. [2]

c

The observatory needs to classify this wave for its optical instruments. Evaluate whether this wave falls within the visible spectrum, using your result from (b) and the known visible range of 400 nm to 700 nm. [1]

Solutions

3QuestionOrder and Properties of EM WavesConcept Practice

3 marks~5 minCriterion A

A hospital imaging department uses four types of electromagnetic wave. Their frequencies are listed below.

Wave type	Frequency (Hz)
Radio	$1 \times 10^{8}$
Microwave	$1 \times 10^{10}$
Visible light	$5 \times 10^{14}$
X-ray	$1 \times 10^{18}$

The speed of light is

c = 3 \times 10^{8}

m s

^{-1}

.

a

State the four wave types in order of increasing frequency. [1]

b

Deduce the wavelength of the X-ray, and explain how the equation

c = f\lambda

shows that frequency and wavelength are inversely proportional for all electromagnetic waves. [2]

Solutions

4QuestionDangers and Precautions of EM RadiationConcept Practice

2 marks~3 minCriterion D

Outline ONE environmental impact that can be caused by increased exposure to ultraviolet (UV) radiation, as shown in the image. The image shows coral reefs that are bleached and dying.

Solutions

5QuestionApplications of Light and Sound in Modern TechConcept Practice

3 marks~5 minCriterion A

The graph below shows signal strength (in dB) against cable length (in km) for an optical fibre. The relationship is linear. The input signal strength at 0 km is 0 dB. From the graph, the signal strength at 10 km is −3 dB.

a

Calculate the attenuation rate of the fibre in dB/km. [1]

b

Deduce the output signal strength after 15 km. [1]

c

A telecommunications engineer states that a signal repeater must be installed before the signal strength falls below −12 dB. Using your attenuation rate, justify the maximum cable length between repeaters. [1]

Solutions

6QuestionApplications of Light and Sound in Modern TechConcept Practice

2 marks~3 minCriterion A

A fibre optic cable carries light signals over long distances. The cable has two main optical layers: a central core (refractive index

n_1 = 1.50

) surrounded by a cladding (refractive index

n_2 = 1.45

).

a

Identify the boundary at which total internal reflection occurs in the cable. [1]

b

The critical angle

\theta_c

for this core–cladding boundary is given by

\sin\theta_c = \dfrac{n_2}{n_1}

. Explain why a light ray travelling in the core at an angle of incidence of 80° to the normal at this boundary remains confined within the core. [1]

Solutions

7QuestionDefinition and Examples of WavesConcept Practice

2 marks~3 minCriterion A

The diagram shows a transverse wave. The distance

X

is marked between two consecutive crests.

a

State the wave property represented by

X

. [1]

b

A sound wave travels at

340 \ \text{m s}^{-1}

and has a frequency of

680 \ \text{Hz}

. Deduce whether

X

for this sound wave would be greater than, equal to, or less than

1 \ \text{m}

. [1]

Solutions

8QuestionApplications Sonar Ultrasound and Musical InstrumentsConcept Practice

2 marks~3 minCriterion A

An oscilloscope displays a pure sound wave. Four points are labelled on the trace:

- A — at a trough (lowest point)
- B — at a crest (highest point)
- C — at the equilibrium (midline)
- D — at the next crest

A double-headed arrow on the diagram indicates the vertical distance from the equilibrium position to the crest.

(a) State what physical quantity the double-headed arrow represents, and identify the letter that marks the point used to measure it. [2]

Solutions

9QuestionLenses Converging and Diverging IntroductoryConcept Practice

2 marks~3 minCriterion A

A converging lens has a focal length of

5 \, \text{cm}

. An object is placed

8 \, \text{cm}

from the lens along the principal axis.

a

Construct the three principal rays for this converging lens, describing each ray's path before and after refraction. [1]

b

Using the lens equation

\dfrac{1}{f} = \dfrac{1}{v} + \dfrac{1}{u}

, calculate the image distance and state two characteristics of the image formed. [1]

Solutions

10QuestionComparing EM Waves Speed Wavelength FrequencyAssessment Practice

4 marks~6 minCriterion A

A mobile phone transmits at a frequency of 900 MHz and a Wi-Fi router transmits at a frequency of 5.0 GHz. Both signals travel at the speed of light,

c = 3.0 \times 10^{8}

m/s.

a

Deduce which signal has the longer wavelength. [1]

b

Calculate the wavelength of the 5.0 GHz Wi-Fi signal using

\lambda = \dfrac{c}{f}

. [2]

c

Analyse which signal diffracts more effectively around large buildings, and justify your answer by comparing the wavelengths of both signals to the scale of the obstacle. [1]

Solutions

11QuestionVisible Light and Color DispersionAssessment Practice

4 marks~6 minCriterion B

White light is shone through a triangular prism, resulting in the dispersion of light into its constituent colors, forming a visible spectrum. The diagram shows the setup and the resulting spectrum.

a

Predict how the visible spectrum would change if the original prism (Prism A) were replaced with another prism of the same shape and size, but made of a material with a higher refractive index (Prism B). Assume the refractive index of Prism B is significantly higher than that of Prism A. [2 marks]

b

Justify your prediction in part (a), explaining how a higher refractive index affects the angles of deviation for different colors of light. Refer to the relationship between refractive index, wavelength, and the amount of bending (deviation) of light as it passes through the prism. [4 marks]

Solutions

12QuestionComparing EM Waves Speed Wavelength FrequencyAssessment Practice

3 marks~5 minCriterion A

Astronomers use electromagnetic waves to study the universe. The table below gives the wavelength of three electromagnetic waves in a vacuum.

Wave type	Wavelength
Radio wave	$1.0$ m
Visible light	$5.0 \times 10^{-7}$ m
X-ray	$1.0 \times 10^{-10}$ m

The speed of all electromagnetic waves in a vacuum is

c = 3.0 \times 10^{8}

m/s.

a

Calculate the frequency of each wave using

c = f\lambda

. [1]

b

Rank the three waves from lowest to highest frequency, and deduce how wavelength and frequency are related for electromagnetic waves travelling at the same speed. [1]

c

A radio telescope detects a signal at

1.5 \times 10^{9}

Hz and an X-ray observatory detects a signal at

3.0 \times 10^{18}

Hz. Analyse why X-ray observatories must be placed in space while radio telescopes can operate on Earth's surface. [1]

Solutions

13QuestionOrder and Properties of EM WavesAssessment Practice

4 marks~6 minCriterion C

The table below shows five types of electromagnetic radiation, their frequencies, and the percentage that passes through Earth's atmosphere.

Type	Frequency (Hz)	Transmission (%)
Radio	$3 \times 10^{6}$	100
Infrared	$3 \times 10^{12}$	20
Visible	$5 \times 10^{14}$	80
Ultraviolet	$3 \times 10^{15}$	0
X-ray	$3 \times 10^{18}$	0

a

Identify the general pattern between frequency and atmospheric transmission shown in the table, and identify one anomaly in that pattern. [2]

b

X-rays have frequency

3 \times 10^{18}

Hz and gamma rays have frequency

3 \times 10^{20}

Hz. Using the relationship

E = hf

, justify which type is more likely to be absorbed by the atmosphere and explain the molecular process responsible. [2]

Solutions

14QuestionComparing EM Waves Speed Wavelength FrequencyAssessment Practice

8 marks~12 minCriterion D

A company plans to launch a constellation of 12,000 satellites to provide global internet access. Each satellite transmits signals at a frequency of 20 GHz. Radio astronomers use telescopes that detect radio waves with wavelengths as short as 1 cm to study cosmic phenomena. The speed of electromagnetic waves in a vacuum is

c = 3.0 \times 10^8

m/s.

a

Calculate the wavelength of the satellite transmission signal. [2]

b

Deduce, using your answer to part (a), whether the satellite signals could interfere with radio telescope observations. [2]

c

Evaluate the ethical and environmental implications of deploying this satellite constellation. In your response, discuss: the benefits of global internet access; the impact on astronomical research; the limitations of using the wave equation alone to predict real-world interference; and a justified recommendation for balancing the competing interests. [4]

Solutions

15QuestionLasers and Optical DevicesAssessment Practice

6 marks~9 minCriterion D

A supermarket uses a laser barcode scanner that emits visible light with a power density of

0.5 \ \text{mW cm}^{-2}

at the scanning window. The maximum permissible exposure (MPE) for the human eye at this wavelength is

1.0 \ \text{mJ cm}^{-2}

.

a

Explain why laser light is capable of damaging retinal tissue, referring to the absorption of energy. [1]

b

Calculate the maximum safe exposure time, in seconds, for an eye accidentally exposed to the scanner beam. Show your working clearly. [2]

c

The supermarket proposes replacing all scanners with models that emit ten times the optical power. Evaluate whether the operational benefit of faster scanning justifies the increased risk of accidental eye exposure in a public setting. Reference your result from part (b) and discuss one limitation of using the MPE standard in this context. [3]

Solutions

16QuestionApplications of Light and Sound in Modern TechAssessment Practice

7 marks~11 minCriterion B

A fiber-optic cable carries a signal from a transmitter. The table shows the measured signal-to-noise ratio (SNR) at different distances.

Distance (km)	1	2	3	4	5	7	9
SNR (dB)	30.0	24.0	19.2	15.4	12.3	7.9	5.0

a

Calculate the decrease in SNR for each 1 km step from 1 km to 5 km. Describe the pattern you observe in these decreases. [2]

b

Deduce the SNR at 6 km. Show your working. [2]

c

Explain why the SNR decreases by a constant factor per kilometre rather than a constant amount, and analyse what this implies about how the fiber affects the signal as it travels further from the transmitter. [3]

Solutions

17QuestionApplications of Light and Sound in Modern TechAssessment Practice

10 marks~15 minCriterion D

Autonomous vehicles use LiDAR (Light Detection and Ranging) sensors to detect objects and map their surroundings. LiDAR emits rapid laser pulses and records the time taken for each pulse to return after reflecting off an object. Manufacturing LiDAR sensors requires semiconductors, rare metals, and precision optical components. In adverse weather, water droplets in fog or heavy rain interact with laser pulses, reducing sensor performance.

a

Explain how LiDAR uses the time-of-flight principle to calculate the distance to an object. [2]

b

Explain two environmental costs arising from the manufacture of LiDAR sensors. [2]

c

A city proposes replacing all human-driven taxis with autonomous vehicles equipped with LiDAR. Evaluate whether the safety benefits of this proposal outweigh its environmental costs, referring to evidence from both parts (a) and (b). [4]

d

Analyse how the interaction between laser pulses and water droplets in fog limits the real-world deployment of autonomous vehicles, and suggest one engineering response to this limitation. [2]

Solutions

18QuestionFiber Optics and Total Internal ReflectionAssessment Practice

6 marks~9 minCriterion C

An experiment investigates total internal reflection across five pairs of materials. For each pair, the incident medium has refractive index

n_1

and the refractive medium has refractive index

n_2

, where

n_2 < n_1

. The critical angle

\theta_c

is measured for each pair.

Pair	A	B	C	D	E
$n_1$	1.33	1.50	1.60	1.70	1.80
$n_2$	1.00	1.10	1.20	1.30	1.40
$\theta_c$ (°)	48.8	47.2	48.6	49.9	51.1

a

Deduce the values of

\sin(\theta_c)

and

\dfrac{n_2}{n_1}

for each pair, recording your results as labelled rows. [2]

b

Construct a graph of

\sin(\theta_c)

against

\dfrac{n_2}{n_1}

and interpret the relationship shown. [2]

c

Analyse the gradient of your graph to evaluate whether the experimental data are consistent with the theoretical relationship

\sin(\theta_c) = \dfrac{n_2}{n_1}

. [2]

Solutions

19QuestionApplications of Light and Sound in Modern TechAssessment Practice

8 marks~12 minCriterion C

A fibre-optic cable transmits light at a bend, where light passes from the core (refractive index

n_1 = 1.50

) into the cladding (refractive index

n_2 = 1.45

). Snell's Law states

n_1 \sin\theta_1 = n_2 \sin\theta_2

. Measured exit angles

\theta_2

for six incident angles

\theta_1

are recorded below.

$\theta_1$ (°)	20	30	40	50	60	70
$\theta_2$ measured (°)	20.7	31.2	42.0	53.4	66.1	80.2

a

Calculate the predicted exit angle

\theta_{2\,\text{pred}}

for each incident angle using Snell's Law. Give each answer to one decimal place. [3]

b

Calculate the percentage discrepancy between the measured and predicted exit angles for each incident angle using:

\text{percentage discrepancy} = \frac{|\theta_{2\,\text{meas}} - \theta_{2\,\text{pred}}|}{\theta_{2\,\text{pred}}} \times 100\%

Give each answer to one decimal place. [2]

c

Evaluate the validity of the ray model for describing light propagation in this fibre-optic cable. Use your discrepancy values to support your judgement, and justify why the ray model becomes less reliable at larger incident angles. [3]

Solutions

20QuestionApplications of Light and Sound in Modern TechAssessment Practice

6 marks~9 minCriterion D

A tech company is planning to install a high-speed internet network in a coastal city that experiences frequent lightning storms and has salty, corrosive air. The company is deciding between optical fibre cables and copper cables.

a

Explain two physics principles that make optical fibre cables well-suited for data transmission in this coastal environment. [2]

b

Explain how the coastal environment creates two distinct physical risks for copper cables, linking each risk to an underlying physics principle. [2]

c

Discuss whether optical fibre or copper cable is the better overall choice for this city. In your answer, evaluate the benefits and limitations of each technology and consider real-world factors that may affect the decision. [2]

Solutions

21QuestionDigital vs Analog Signals IntroductoryAssessment Practice

10 marks~15 minCriterion A

An oscilloscope displays the input and output signals of an analog sine wave and a digital square wave, each transmitted through the same optical fibre of length 12 km. The timebase is set to

2\ \mu\text{s}

/division. Both input signals are aligned at

t = 0

. The output sine wave peak occurs at 4.2 divisions from the input; the output square wave leading edge occurs at 4.0 divisions from the input.

a

Calculate the propagation time delay for the analog signal. [2]

b

Using

v = \dfrac{d}{t}

, calculate the speed of light in the fibre using the analog signal delay. Show your working clearly. [3]

c

The digital signal delay is shorter than the analog signal delay. Analyse what this difference reveals about how each signal type propagates through the fibre, and explain one consequence for the design of long-distance communication systems. [5]

Solutions

22QuestionDefinition and Examples of WavesAssessment Practice

4 marks~6 minCriterion A

A loudspeaker cone vibrates back and forth to produce sound. The speed of sound in air is 340 m s

^{-1}

.

a

Define the terms compression and rarefaction as they apply to a longitudinal wave. [1]

b

Explain how the motion of the loudspeaker cone produces alternating compressions and rarefactions in the surrounding air. [2]

c

The loudspeaker's frequency is increased while the speed of sound remains constant. Analyse how this change affects the spacing and number of compressions and rarefactions produced per second. [1]

Solutions

23QuestionDefinition and Examples of WavesAssessment Practice

4 marks~6 minCriterion C

Water waves spread outward from a stone dropped into a still pond. A small cork floats on the surface near the point of impact. The diagram shows circular wavefronts spreading from the source, with the cork positioned between two adjacent wavefronts.

a

Identify the wave type (transverse or longitudinal) that a water surface wave represents. [1]

b

Describe the motion of the cork as a water wave passes beneath it. [1]

c

Analyse whether the water itself travels outward from the source as the wave spreads. Use the observed motion of the cork as evidence to support your reasoning. [2]

Solutions

24QuestionDefinition and Examples of WavesAssessment Practice

8 marks~12 minCriterion A

Two sinusoidal waves travel simultaneously along the same string. A displacement–time graph shows:

Wave A: period

2.0 \, \text{ms}

, amplitude

3 \, \text{mm}

, wavelength

0.40 \, \text{m}

Wave B: period

4.0 \, \text{ms}

, amplitude

3 \, \text{mm}

, wavelength

0.80 \, \text{m}

a

Deduce the frequency of each wave from the graph data. [2]

b

Calculate the wave speed of each wave using

v = f\lambda

. Show your working. [2]

c

Analyse what the calculated speeds reveal about how wave speed depends on the properties of the medium, and explain why Wave A and Wave B have different wavelengths despite travelling in the same string. [4]

Solutions

25QuestionDefinition and Examples of WavesAssessment Practice

6 marks~9 minCriterion B

A student investigates how wave speed on a stretched spring depends on tension. The frequency is kept constant at 5.0 Hz. Wavelength is measured at five tensions and wave speed is calculated using

v = f\lambda

.

Tension (N)	2.0	4.0	6.0	8.0	10.0
Wavelength (m)	0.40	0.57	0.69	0.80	0.89
Wave speed (m/s)	2.00	2.85	3.45	4.00	4.45

a

Construct a graph of wave speed (y-axis) against tension (x-axis) and describe the shape of the curve. [2]

b

Deduce the wave speed when the tension is 12.5 N, showing clearly how the data support your reasoning. [2]

c

Analyse why increasing tension causes wave speed to increase, referring to the restoring force and the property of the spring that remains constant throughout the investigation. [2]

Solutions

26QuestionWave Parameters Wavelength Frequency AmplitudeAssessment Practice

5 marks~8 minCriterion C

Two graphs describe a wave passing through a medium.

Displacement–time graph (single point observed over time):

Time (s)	0.00	0.05	0.10	0.15	0.20	0.25	0.30
Displacement (m)	0.0	0.4	0.0	−0.4	0.0	0.4	0.0

Displacement–distance graph (snapshot of the wave at one instant):

Distance (m)	0.0	0.2	0.4	0.6	0.8	1.0	1.2
Displacement (m)	0.0	0.5	0.0	−0.5	0.0	0.5	0.0

a

State the period, frequency, and amplitude from the displacement–time graph, and state the wavelength and amplitude from the displacement–distance graph. [2]

b

Calculate the wave speed using parameters from both graphs combined. [1]

c

The two graphs give different amplitude values. Justify which amplitude measurement is more reliable, using the wave speed result and the nature of each graph as evidence. [2]

Solutions

27QuestionSpeed of a Wave v = f lambdaAssessment Practice

4 marks~6 minCriterion C

A guitar string vibrates at 330 Hz, producing a sound wave with a wavelength of 1.0 m in air. A student claims that changing the vibration frequency alone is sufficient to change the speed of the sound wave.

a

State the equation relating wave speed, frequency, and wavelength. [1]

b

Calculate the speed of the sound wave. Give your answer in m s

^{-1}

. [1]

c

Analyse whether the student's claim is correct. Use

v = f\lambda

and your knowledge of how sound speed is determined in a medium to justify your answer. [2]

Solutions

28QuestionDefinition and Examples of WavesAssessment Practice

6 marks~9 minCriterion D

A coastal community is evaluating a proposal to install a wave-energy converter array 2 km offshore. The converters reduce incoming wave heights by 30%. The local surfing industry requires wave heights of at least 1.5 m, and the marine ecosystem depends on wave-driven sediment transport to maintain beach habitats.

Incoming wave data: speed

v = 8\ \text{m/s}

, frequency

f = 0.2\ \text{Hz}

, amplitude

A = 2.0\ \text{m}

, seawater density

\rho = 1025\ \text{kg/m}^3

.

Power per unit width:

P = \dfrac{1}{2}\rho v \omega^2 A^2

, where

\omega = 2\pi f

.

a

Show that the power per unit width of the incoming waves is approximately

2.59 \times 10^4\ \text{W/m}

. [2]

b

Calculate the power per unit width of the waves after the 30% height reduction. [2]

c

Evaluate the ethical trade-off between the renewable energy gained and the potential loss of surfing culture and ecological function. In your answer, identify two limitations of using this energy model to predict ecological impact. [2]

Solutions

29QuestionSpeed of a Wave v = f lambdaAssessment Practice

8 marks~12 minCriterion D

In a ripple tank experiment, water waves are generated at several frequencies. The frequency

f

(in Hz) and corresponding wavelength

\lambda

(in m) are recorded. A graph is plotted with

\dfrac{1}{\lambda}

(in m

^{-1}

) on the x-axis and

f

(in Hz) on the y-axis. The best-fit line passes through the origin with gradient

0.35\ \text{m s}^{-1}

.

The accepted wave speed at this water depth is

0.40\ \text{m s}^{-1}

.

a

Deduce the experimental wave speed from the gradient of the graph. [2]

b

Explain why plotting

\dfrac{1}{\lambda}

against

f

produces a straight line through the origin, and identify the physical quantity represented by the gradient. [3]

c

Analyse the experimental result by calculating the percentage discrepancy between the experimental and accepted wave speeds, and evaluate whether wavelength or frequency measurement is the more likely dominant source of error. [3]

Solutions

30QuestionSpeed of a Wave v = f lambdaAssessment Practice

7 marks~11 minCriterion B

A student investigates how the speed of water waves depends on wavelength. She generates waves in a ripple tank and measures the period

T

(in seconds) for different wavelengths

\lambda

(in meters). The data points are plotted on a graph of

\lambda

(horizontal axis) vs

T

(vertical axis). The graph shows a curve that passes through the points:

(0.10, 0.20)

,

(0.20, 0.28)

,

(0.30, 0.35)

,

(0.40, 0.40)

,

(0.50, 0.45)

. [Note: The graph should be drawn with

\lambda

from 0 to 0.6 m and

T

from 0 to 0.5 s, with a smooth curve through the points.]

a

[2 marks] Calculate the wave speed

v = \lambda / T

for each data point. Record your results in a table.

b

[2 marks] Describe the pattern in the calculated wave speeds. What does this suggest about the relationship between wave speed and wavelength for these waves?

c

[2 marks] The wave equation is

v = f \lambda

, where

f = 1/T

. Using your results, determine whether the frequency

f

is constant or varies as

\lambda

changes. Justify your answer.

Solutions

31QuestionApplications Sonar Ultrasound and Musical InstrumentsAssessment Practice

3 marks~5 minCriterion A

An ultrasound pulse is emitted at

t = 0\ \mu\text{s}

and travels through layers of skin, fat, and muscle. The first reflected pulse returns at

t = 13\ \mu\text{s}

with an amplitude equal to

80\%

of the emitted pulse. The second reflected pulse returns at

t = 26\ \mu\text{s}

with an amplitude equal to

40\%

of the emitted pulse.

a

State one mechanism by which the ultrasound pulse loses energy as it travels through biological tissue. [1]

b

Explain how acoustic impedance mismatch at a tissue boundary determines the amplitude of a reflected pulse. [1]

c

Using the data provided, explain why the second reflected pulse has a smaller amplitude than the first. [1]

Solutions

32QuestionPitch Loudness and Frequency RelationshipAssessment Practice

6 marks~9 minCriterion D

A medical technician uses a 5 MHz ultrasound transducer to image a fetus at a depth of 12 cm. The speed of ultrasound in soft tissue is approximately 1500 m s

^{-1}

. Reflections occur at boundaries between tissues of different densities, including amniotic fluid, muscle, fat, and bone.

a

Calculate the wavelength of the 5 MHz ultrasound in soft tissue. [1]

b

Explain how increasing the ultrasound frequency would affect both image resolution and penetration depth, and identify one benefit and one limitation this creates for fetal imaging. [3]

c

Discuss how the assumption of uniform tissue density limits the accuracy of the ultrasound image, referring to at least two different tissue types present. [2]

Solutions

33QuestionPitch Loudness and Frequency RelationshipAssessment Practice

5 marks~8 minCriterion B

A student investigates sound waves in air at 20°C by measuring the wavelength

\lambda

at different periods

T

. The graph shows

\lambda

(m) against

T

(ms); a straight line passes through the origin and the following data points:

$T$ (ms)	1.0	2.0	3.0	4.0	5.0
$\lambda$ (m)	0.343	0.686	1.029	1.372	1.715

Use

f = \dfrac{1}{T}

and

v = f\lambda

.

a

Calculate the speed of sound for the data point

T = 3.0

ms,

\lambda = 1.029

m. Show your working. [2]

b

Deduce what the gradient of the

\lambda

–

T

graph represents physically, and calculate its value. [1]

c

Analyse whether the graph supports the claim that the speed of sound in air at 20°C is independent of frequency. Use evidence from at least two data points in your answer. [2]

Solutions

34QuestionProduction and Transmission of SoundAssessment Practice

5 marks~8 minCriterion C

A student investigates sound waves in air at 20°C by measuring frequency

f

and wavelength

\lambda

for five notes. The results are plotted as a graph of

\frac{1}{\lambda}

against

f

.

f

(Hz): 200, 400, 600, 800, 1000

\frac{1}{\lambda}

(m

^{-1}

): 0.583, 1.167, 1.750, 2.333, 2.917

a

State the wave equation linking

v

,

f

, and

\lambda

, and show that the gradient of the graph equals

\frac{1}{v}

. [1]

b

Calculate the speed of sound in air at 20°C using the gradient of the line of best fit. [2]

c

A student claims that the same graph could be used, without any new measurements, to determine the speed of sound at 0°C, since the relationship

v = f\lambda

still holds. Evaluate this claim. [2]

Solutions

35QuestionSpeed of Sound in Solids Liquids and GasesAssessment Practice

4 marks~6 minCriterion D

A mining company plans to use seismic surveys to locate mineral deposits beneath land belonging to an indigenous community. Small explosions at the surface generate P-waves (speed

6000 \ \text{m/s}

in rock) and S-waves (speed

3500 \ \text{m/s}

in rock). Sensors are placed

2 \ \text{km}

from each explosion site.

a

Calculate the time difference between the arrival of the P-wave and the S-wave at a sensor

2 \ \text{km}

from the explosion. Show your working. [2]

b

The indigenous community opposes the survey, citing disruption to wildlife and sacred sites; the company argues economic necessity. Using your result from (a) and your knowledge of wave behaviour in rock, evaluate the scientific, environmental, and ethical implications of conducting seismic surveys in this context. [2]

Solutions

36QuestionSpeed of Sound in Solids Liquids and GasesAssessment Practice

3 marks~5 minCriterion C

The table below shows the speed of sound

v

and density

\rho

for four solid materials.

Material	$v$ (m/s)	$\rho$ (kg/m³)
Aluminium	6420	2700
Steel	5960	7800
Glass	5640	2500
Rubber	1500	1100

a

Construct a graph of

v

(y-axis) against

\rho

(x-axis) for the four materials and describe the relationship shown. [1]

b

Deduce, using your graph, the speed of sound in copper, which has a density of 8960 kg/m³. [1]

c

Rubber and glass have similar densities yet their speeds of sound differ by over 4000 m/s. Analyse what this suggests about density as the sole factor determining the speed of sound in solids. [1]

Solutions

37QuestionApplications Sonar Ultrasound and Musical InstrumentsAssessment Practice

6 marks~9 minCriterion A

A clarinet behaves as a tube closed at one end and open at the other. The diagram below shows the fundamental standing wave inside a clarinet of length

L = 0.60 \text{ m}

, with a node at the closed end and an antinode at the open end.

a

Explain, using wave reflection, why a node forms at the closed end and an antinode forms at the open end. [2]

b

Show that the fundamental wavelength is

\lambda = 4L

, and calculate the fundamental frequency given that the speed of sound in air is

340 \text{ m/s}

. [2]

c

A player presses keys to shorten the effective tube length. Analyse how this changes the standing wave pattern inside the clarinet and evaluate the effect on the pitch of the note produced. [2]

Solutions

38QuestionRay Diagrams and Image Formation BasicsAssessment Practice

3 marks~5 minCriterion C

A student investigates refraction as light passes from air into a glass block. The table shows the angle of incidence

i

and angle of refraction

r

for four trials.

Trial 1	$i = 20°$	$r = 13°$
Trial 2	$i = 30°$	$r = 19°$
Trial 3	$i = 45°$	$r = 28°$
Trial 4	$i = 60°$	$r = 35°$

Snell's law for light entering glass from air:

n = \dfrac{\sin i}{\sin r}

a

Using Trial 2, calculate the refractive index

n

of the glass. [1]

b

A second student uses Trial 4 to calculate

n

and obtains a different value. Deduce whether the two results are consistent with the glass having a single refractive index, and identify one source of experimental uncertainty that could account for any difference. [1]

c

Evaluate whether the glass could be used to achieve total internal reflection when light travels from the glass into air, given that the critical angle

\theta_c

is related to refractive index by

\sin \theta_c = \dfrac{1}{n}

. [1]

Solutions

39QuestionRefraction Through Glass Blocks and WaterAssessment Practice

4 marks~6 minCriterion B

Investigate the refraction of light through a glass block. The diagram shows three incident rays (A, B, C) passing from air into a glass block at different angles to the normal. The angles of incidence and refraction are measured and recorded below.

Ray A: angle of incidence = 0°, angle of refraction = 0°
Ray B: angle of incidence = 30°, angle of refraction = 19°
Ray C: angle of incidence = 60°, angle of refraction = 35°

a

[2 marks] Describe the pattern in the data. How does the angle of refraction change as the angle of incidence increases?

b

[2 marks] Using the pattern you identified, predict the angle of refraction for an incident angle of 45°. Explain your reasoning.

c

[2 marks] Justify why the relationship between angle of incidence and angle of refraction is not a simple linear proportion (i.e., doubling the incident angle does not double the refracted angle). Use the data to support your answer.

Solutions

40QuestionRay Diagrams and Image Formation BasicsAssessment Practice

8 marks~12 minCriterion C

A student investigates Snell's Law by passing a narrow beam of light from air into an unknown transparent medium. The angles of incidence (

i

) and refraction (

r

) are recorded below.

i

(°): 10, 20, 30, 40, 50, 60, 70

r

(°): 6.5, 13.0, 19.5, 25.5, 31.5, 37.0, 42.0

Snell's Law:

n_1 \sin i = n_2 \sin r

, where

n_1 = 1.00

for air.

a

Calculate

\sin i

and

\sin r

for each pair of angles. Record all values to three decimal places. Then plot

\sin i

(vertical axis) against

\sin r

(horizontal axis) on the axes provided. [3]

b

Draw a line of best fit on your graph. Deduce the gradient of the line, showing clearly which two points on the line you used. [3]

c

The accepted refractive index of glass is 1.52. Evaluate whether the unknown medium could be glass, using your gradient and Snell's Law to justify your conclusion. [2]

Solutions

41QuestionLenses Converging and Diverging IntroductoryAssessment Practice

6 marks~9 minCriterion D

A student notices that inexpensive reading glasses produce blurry images at the lens edges, while premium eyeglasses remain sharp across the entire lens. Investigation reveals that inexpensive glasses use spherical converging lenses and premium glasses use aspherical converging lenses.

a

Construct ray diagrams for a spherical converging lens and an aspherical converging lens. For each, show at least three parallel rays from a distant object converging toward a focal point. Label the focal point(s) and indicate where spherical aberration occurs in the spherical lens. [2]

b

Explain one advantage of aspherical lenses for a person who wears reading glasses. [2]

c

Evaluate whether aspherical lenses are always the better choice for eyeglass users, considering manufacturing cost and individual visual requirements. [2]

Solutions

42QuestionLenses Converging and Diverging IntroductoryAssessment Practice

6 marks~9 minCriterion D

Uncorrected myopia affects an estimated 2.5 billion people globally, with the highest burden in low-income regions where converging lens eyeglasses remain inaccessible to many.

a

State what a converging lens does to parallel rays of light and identify the lens property that determines the strength of correction needed for myopia. [1]

b

The thin lens equation is

\dfrac{1}{f} = \dfrac{1}{u} + \dfrac{1}{v}

. A patient's near point is 1.0 m and their far point is 0.25 m. Calculate the focal length of the corrective lens required so that an object at infinity is focused at the patient's far point. [2]

c

Evaluate the extent to which the thin lens model and economic or infrastructural barriers together limit the effectiveness of converging lens eyeglasses as a global solution to myopia. [3]

Solutions

43QuestionLenses Converging and Diverging IntroductoryAssessment Practice

5 marks~8 minCriterion C

A student investigates a converging lens by placing an object at several distances and recording the corresponding image distances. The results are plotted as a graph of

\dfrac{1}{v}

(y-axis) against

\dfrac{1}{u}

(x-axis). The line of best fit has a gradient of

-1.0

and a y-intercept of

0.050 \text{ cm}^{-1}

.

The thin lens equation is:

\frac{1}{f} = \frac{1}{u} + \frac{1}{v}

a

Deduce the focal length

f

of the lens using the y-intercept. [2]

b

Explain how the gradient of

-1.0

is consistent with the thin lens equation. [1]

c

Analyse what a measured gradient of

-0.85

instead of

-1.0

would suggest about the reliability of the experimental data. [2]

Solutions

44QuestionLenses Converging and Diverging IntroductoryAssessment Practice

4 marks~6 minCriterion A

A camera lens used in portrait photography is a converging lens with focal length

f = +15

cm. A subject stands

u = 25

cm from the lens.

\frac{1}{f} = \frac{1}{v} + \frac{1}{u}

a

Calculate the image distance

v

. [2]

b

Deduce whether the image is real or virtual, and state on which side of the lens it forms. [1]

c

Explain why a converging lens cannot form a real image when the object is placed closer to the lens than its focal point. [1]

Solutions

Waves Sound and Light — Free MYP5 Physics Practice Questions